Cerebral Perfusion And Metabolic Status Changes With The FVH Signs In Patients With Unilateral Middle Cerebral Artery Stenosis By Multimodal MRI Technology

Objective:To investigate the consistency of flair vascular hyperintensity?FVH?and arterial transit artifact?ATA?in three-dimensioned arterial spin labelling?3D-ASL?,and to quantitatively analyze their corresponding cerebral blood flow?CBF?,cerebral oxygen and acid-base metabolism changes in patients with unilateral middle cerebral artery?MCA?stenosis by using multi-modal MRI sequences.Materials and Methods:There were two parts in this study.?1?Forty-six patients with MCA stenosis or occlusion were collected the in the First Affiliated Hospital of Dalian Medical University.Their clinical and laboratory examination data were obtained.All patients underwent multimodal MR scanning included routine MRI sequences and3D-ASL.Two radiologists measured and evaluated the degree of MCA stenosis,the incidence of FVH sign and ATA.ATA including two post labeling delay time?PLD?,defined as ATA_1.5and ATA_2.5.The CBF value(CBF_1.5,CBF_2.5)of M1-M6 area in infarcted hemisphere based on two PLD was measured.The difference and consistency of FVH and ATA?with 1.5 s and 2.5 s of post-labelling delay?,ATA_1.5and ATA_2.5were analysed by chi square test and kappa test.The differences of CBF were compared between two groups with or without FVH sign by independent-sample t-test.Spearman correlation test was used to analyze the relationships between FVH sign?ATA sign and vascular stenosis?clinical data.The influencing factors of FVH sign and ATA were analyzed by binary logistic regression.The difference was statistically significant at p<0.05.?2?Twenty-eight subacute cerebral infarction patients hospitalized in the First Affiliated Hospital of Dalian Medical University from April to November 2019 were prospectively collected.The clinical and laboratory data of all patients were recorded,and the National Institute of Health stroke scale?NIHSS?scores at admission and discharge were evaluated by a neurologist(NIHSS_admission,NIHSS_discharged).All subjects underwent MRI examinations,including T1WI,T2WI,T2 FLAIR,3D TOF MRA,Diffusion weighted Imaging?DWI?,Susceptibility weighted imaging?SWI?and Amide proton transfer?APT?sequences.The degree of MCA stenosis,the score of FVH and asymmetrically prominent cortical veins?APCVs?on SWI were measured and evaluated independently by two radiologists.The phase values of the vein around the lesion were measured,and the phase difference????and ratio?r???were calculated.The 3D ADC value and 3D APTW value were obtained according to APT and ADC image,including the maximum(APTW_max)?minimum(APTW_min)and mean(APTW_mean),and APT difference(APTW_max-min)and ratio(r APTW_mean)were calculated.All patients were divided into mild-moderate stenosis group and severe stenosis group.The differences between FVH and APCVs score of two groups were compared by independent sample t test.Spearman correlation analysis were separately used to analyze the relationships between FVH scores and imaging parameters?clinical scores in three groups?whole,mild-moderate stenosis group and severe group?,and multiple linear regression analysis was used to explore the influencing factors of FVH scores.Results:?1?In forty-six patients with unilateral MCA stenosis or occlusion,there was no difference between FVH and ATA_1.5?ATA_2.5??²=21.60,p=0.45;?²=6.13,p=0.12?,ATA_1.5and ATA_2.5??²=15.15,p=0.34?.The incidence of FVH sign was consistent with ATA_1.5and ATA_2.5?kappa=0.68,p<0.01,kappa=0.35,p=0.01?;the incidence of ATA_1.5and ATA_2.5was also consistent?kappa=0.57,p<0.01?.CBF_1.5sof FVH positive group was slightly lower than that of negative group,while CBF_2.5swas slightly higher than that of negative group,but there was no statistical difference?p>0.05?.The incidence of FVH sign?r=0.38,p=0.01?,ATA_1.5?r=0.58,p=0.00?were correlated with the degree of vascular stenosis,there was no correlation between the incidence of ATA_2.5and the degree of vascular stenosis?r=0.26,p=0.08?.Age,systolic blood pressure,diastolic blood pressure and HDL were all correlated with both FVH sign and ATA?r=-0.37,-0.34,-0.49,-0.39,p=0.01,0.02,0.00,0.01;r=-0.39,-0.38,0.46,-0.35,p=0.00,0.01,0.00,0.02?.In addition,HCY was negatively correlated with ATA?r=-0.31,p=0.03?.NIHSS_admissionscore was the influencing factor of FVH score?B=0.239,95%CI:0.445-0.032;p=0.025?.?2?In twenty-eight patients with unilateral MCA stenosis and cerebral infarction,the scores of FVH and APCVs in the severe stenosis group were significantly higher than those in the mild-moderate stenosis group?t=3.13,p=0.001;t=5.45,p=0.00?.On unified comparison,FVH score was positively correlated with APCVs score,r?,NIHSS _admissionscore?r=0.60,p=0.001;r=0.39,p=0.04;r=0.43,p=0.02?,and negatively correlated with ADC value?r=-0.40,p=0.03?.There was no correlation between FVH score and APTW_max,APTW_min,APTW_mean,APTW_max-min,r APTW_mean,NIHSS _discharge?p>0.05?.Conclusion:1.The FVH has consistency with ATA in patients with unilateral MCA stenosis or occlusion,and both of them can be considered as indicators of the collateral circulation.The FVH seem to be little effect on regional cerebral blood flow perfusion.2.The incidence of FVH and ATA are related to the stenosis of the responsible artery,while the aged,hypertension and HDL decrease the incidence of both signs.3.The ranges of FVH and APCVs are related to the stenosis of the responsible artery.The larger territory of FVH is consistent with more obvious hypoxia and severe cytotoxic edema and indicated the more serious condition in patients with cerebral infarction.FVH ranges have no significant effect on acid-base metabolism.